Insertion magnetic meters and methods

ABSTRACT

A magnetic insertion meter is disclosed herein. Disclosed insertion meters include in some examples, a sensor head tube cylinder having a textured front surface and at least two electrodes. Disclosed insertion meters include a textured front surface adapted to move the separation point of a fluid flowing over the sensor head tube towards the upstream surface as compared to the same sensor head tube without the textured front surface. Methods of measuring flow are also disclosed herein using example magnetic insertion meters.

RELATED APPLICATIONS

This application claims priority to U.S. provisional application62/809,252, filed on Feb. 22, 2019, the entirety of which isincorporated by reference herein.

FIELD OF USE

This application relates to flow meters and more particularly tomagnetic insertion meters.

BACKGROUND

Two of the most important characteristics of a precision flow meter arerepeatability and linearity. Repeatability is the ability of a meter toobtain the same results under the same conditions. Linearity is thedegree to which a meter's output is linear to the amount of flow beingtransferred through a pipe or other conduit.

It is difficult to make an accurate meter if it is not repeatable. It isalso difficult to calibrate and predict performance in various operatingconditions (for example, fluids, temperatures, and pipe types) if it isnot linear. Insertion flow meters are typically less accurate thanin-line meters because they have worse repeatability and linearity thanan in-line meter. This is in part because insertion meters by the natureof their design can only measure a point on the velocity profile, or atlease only a small portion thereof, and this measurement must becorrelated to estimate the average velocity of flow through the pipe.The shape of the velocity profile changes with flow, pressure, andtemperature, among other factors, which affects the translation of thispoint measurement to total average velocity. Inline meters, on the otherhand, measure across the entire velocity profile enabling an accuratedirect measurement of the average velocity of flow through the pipe.Consequently, insertion magnetic meters may typically have an accuracyof +/−2% of reading, whereas in-line meters have accuracies as low as+/−0.2% of reading.

However, insertion meters are advantageous as compared to in-line metersbecause insertion meters are modular and do not require complete systemshutdown for installation and repair. In addition, insertion meters costless and have a lower installation cost. To install an inline meter, thesystem has to be shut down, a section of pipe cut out, flanges welded inplace and then the meter is mounted between the two flanges. Insertionmeters can be mounted though a common ball valve.

Any advancement that enables the improvement of either the repeatabilityof the accuracy of an insertion meter is extremely valuable.

SUMMARY

In one aspect of the disclosure, a magnetic insertion meter is disclosedhaving a sensor head cylinder having a textured front surface and atleast two electrodes. In another aspect of the disclosure, an insertionmeter includes a field coil configured to emit an alternating magneticfield when energized with an alternating current. In yet another aspectof the disclosure, a textured front surface is an upstream surface. Inone aspect of the disclosure a textured front surface is at least one ofan abrasive on a substrate, an impregnated abrasive, a depositedabrasive, and/or an abrasive layer. In one particular aspect of thedisclosure, a textured front surface is sandpaper. In another aspect ofthe disclosure a textured front surface has a higher roughness than amaterial forming the sensor head tube.

In one aspect of the disclosure, a textured front surface includes atleast one groove. In another aspect of the disclosure, a textured frontsurface includes two grooves extending along the longitudinal axis ofthe sensor head cylinder. In one aspect of the disclosure, a texturedfront surface includes dimples. In another aspect of the disclosure, aplurality of dimples are equally spaced apart from each other. Inanother aspect of the disclosure, a plurality of dimples form a patternin which three of the plurality of meters form an equilateral triangle.In one aspect of the disclosure, a textured front surface includes aplurality of columns of dimples. In one aspect of the disclosure, atextured front surface includes from about 3 to about 7 columns ofdimples. In another aspect of the disclosure a textured front surfaceincludes dimples. In yet another aspect of the disclosure a texturedfront surface is adapted to alter the boundary layer of a fluid flowingover the sensor head tube as compared to the same sensor head tubewithout the textured front surface. In another aspect of the disclosurea textured front surface is adapted to move the separation point of afluid flowing over the sensor head tube towards the front surface ascompared to the same sensor head tube without the textured frontsurface. In one aspect of the disclosure, a textured surface is asurface contour.

In one aspect of the disclosure, a method of measuring flow is disclosedin which the method includes providing a magnetic insertion meter thatincludes a sensor head cylinder having a textured front surface and atleast two electrodes and measuring the output of said electrodes. Inanother aspect of the disclosure a textured front surface is at leastone of an abrasive on a substrate, an impregnated abrasive, a depositedabrasive, and/or an abrasive layer. In another aspect of the disclosure,a textured front surface includes at least one of dimples and/orgrooves.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example insertion meter.

FIGS. 2, 3, 4 and 5 are views like FIG. 1 depicting example flowconditions.

FIG. 6 is a graph depicting meter factor of the meter of FIG. 1.

FIG. 7 is a schematic view of an example insertion meter in accordancewith disclosed embodiments.

FIG. 8 is a graph depicting meter factor of the meter of FIG. 6.

FIG. 9 is a schematic view of an example insertion meter in accordancewith disclosed embodiments.

FIG. 10 is a perspective view of an example insertion meter inaccordance with disclosed embodiments.

FIGS. 11 and 12 show flow velocity stream models of the insertion metersof FIG. 1 and FIG. 10, respectively.

FIG. 13 is a graph depicting meter factor of insertion meters inaccordance with disclosed embodiments.

DETAILED DESCRIPTION

FIG. 1 shows a cross section of an insertion meter 100, having the shapeof a cylinder, looking down the longitudinal access of an exampleinsertion meter 100. The insertion meter 100 may be, for example, partof the example sensor assemblies described in U.S. application Ser. No.16/233,915, filed on Dec. 27, 2018, titled “Scalable Monolithic SensorAssembly, Controller, and Methods of Making and Installing Same,” andpublished as US 2019/0204129, the entirety of which is included hereinas Appendix A and also is incorporated by reference herein. The crosssection is taken at electrodes 110.

The insertion meter 100, includes a cylindrical sensor head tube 140,that is inserted into the pipe carrying a suitably conductive fluid 180.In operation, the insertion meter 100 generates a magnetic field usingfield coils energized by an alternating current. The conductor (i.e.,the conductive fluid) passing through the magnetic field induces anelectric potential and current according to Faraday's law, which isindicative of the flow velocity. The insertion meter 100 measures theelectrical potential (voltage or “V”) generated by the flow velocitybetween at least two electrodes. Such a potential difference may bemeasured, for example, between at least one top electrode and at leastone bottom electrode.

For example, the insertion meter 100 may have 2 or more electrodesdisbursed from top to bottom of its longitudinal axis. In one particularexample the insertion meter 100 may include 1 or more top electrodes,one or more bottom electrodes, and one or more center electrodes. Thecenter electrodes act as an electrical reference, whereas the voltagepotential is sampled between pairs of top and bottom electrodes. The twoelectrodes 110 shown in FIG. 1 share the same longitudinal height. Thus,the electrodes 110, may each be top electrodes, bottom electrodes, orreferences electrodes. The electrodes 110 shown in FIG. 1 may beelectrically connected to form a single electrode or they beelectrically isolated from each other to form two independentelectrodes. In an example independent configuration in which theelectrodes 110 are bottom electrodes, a first potential could bemeasured between one of the electrodes 110 and a respective topelectrode and a second potential could be measured between the otherelectrode 110 and a different top electrode.

The repeatability of the fluid flow around previous insertion meters 100can be improved. FIG. 2 shows insertion meters 100 in a flowing fluid180 at an example velocity in the direction of the arrows 182. If, forexample, the flowing fluid 180 at arrows 182 represent a bulk fluid thatis turbulent. as shown, the flowing fluid reaches a stagnation point186, at which the fluid flow is a minimum, when the fluid contacts thefront surface 120. The fluid 180 also forms a laminar boundary layer 184(or boundary layer 184), which is a transition between the stagnationpoint and the bulk terminal flow 182, as it contacts the front surface120 facing the oncoming fluid flow. The front surface 120, i.e., thesurface facing the oncoming fluid flow, will also be referred to hereinas the upstream surface. It should be noted that the if the fluid flowwere to reverse directions, the opposing surface would become theupstream surface. The boundary layer 184 becomes unstable or otherwisetransitions away from the surface of the insertion meter 100 as it flowstowards the back 122, or downstream surface, of the insertion meter 100.This boundary layer transition is indicated as separation point 105.

The location of the separation point 105 is not consistent because fluidflow is chaotic and it is affected by changes in the amount of fluidflow across the insertion meter 100, as well as fluid characteristics,for example, velocity of the fluid, temperature, viscosity, density, andsurface finish of the cylinder. In addition, the location of theseparation point 105 can also change based on whether the flow rate isincreasing or decreasing to a given velocity. FIGS. 3 through 5 showthree different velocities of the same fluid in increasing order, i.e.,the FIG. 5 fluid velocity is higher than the fluid velocity of FIG. 4,which is higher than the fluid velocity of FIG. 3. In FIG. 3, separationpoint 105 a is typically between the electrodes 110 and back 122. InFIG. 4, the velocity of the fluid is greater than that of FIG. 3 andless than that of FIG. 5 and the separation point 105 b has shifted tonear electrode 110. In FIG. 5, the velocity of the fluid is more thanthat of FIG. 3 and FIG. 4 and separation point 105 c has shifted closerto the front 120 of insertion meter 100, i.e., closer to the directionfrom which the fluid is flowing. While not being bound by theory, it isbelieved that the inconsistencies in the boundary layer/separation point105 (105 a,105 b,105 c) location contribute to the decrease in linearityand repeatability experienced with prior insertion meters. That is, anunstable boundary layer at the sensor electrodes 110 can preventaccurate and repeatable results as compared to a more stable boundarylayer. For example, based on inconsistencies in the fluid flow orchanges in the flow rate, at some conditions the separation point 105 ais closer to electrode 110 (whether downstream or upstream) which, inthe right conditions, can cause more variance in the measurements takenat electrode 105 a. While the separation point 105 c of FIG. 5 has beshifted towards front surface 120, the variation in the boundary layershown between FIG. 3 through FIG. 5 can cause an insertion meter 100 todeviate from calibration.

FIG. 6 shows example meter outputs (1P-RUN1 through 1P-RUN5) of anexample insertion meter 100 (FIG. 1) as a graph of meter factorexpressed as (LPIP Pulse/Isoil Gal) against nominal flow rate expressedin feet per second (ft/s). The meter factor (or correction factor) isnormally dimensionless and is calculated as the ratio of the meteroutput to value determined by a standard reference meter, for exampleInsertion Meter Pulse/Reference (Ref) Meter Pulse This can be computedfrom rate measurements or quantity measurements. The different linetraces show repeated test runs of the same insertion meter 100 under thesame conditions. It is shown that both repeatability and linearity canbe improved. For the test case shown in FIG. 6, the best accuracyachievable using a constant Meter Factor would be +/−3% of reading. Forreference, an ideal sensor would produce a constant meter factorregardless of flow rate being measured (horizontal line) meaning theoutput of the meter is linear with flow and can be easily corrected bymultiplying the meter output by a constant meter factor. While an idealmeter is likely not possible, linearity in the meter factor is desired.Linearity simplifies calibration, that is it is more simple to fit ameter reading to a two-point line as compared to a complex curve fit,e.g. like the complex curve of FIG. 6, which would require multiplecharacterizations. Linearity also simplifies corrections to otheroperating conditions, improves reproducibility between meters (unit tounit variation), shortens the manufacturing validation cycle to confirmaccuracy of the meter, and limits the need to test multiple meters unitsto determine characteristic curve, that is, fewer units are required tocharacterize multiple pipes/sizes. If the meter factor is constant, itis assumed, while the value may change, it will be constant for otherfluids or flow conditions. It is much easier to determine correctionsfor other flow conditions and fluids if the relationship is linear.

Attempts to improve reproducibility have previously been made to changethe placement of the electrodes by rotating each electrode towards therear the insertion meter, i.e., away from the front 120 of insertionmeter 100. This places the electrodes within the laminar boundary layerbefore it transitions to a turbulent boundary layer. While this could,hypothetically, mitigate some effects of the unstable boundary layer byforcing a consistent velocity profile, it would also result in adecrease of sensor signal, which is not advantageous because itdecreases the signal to noise ratio.

FIG. 7 shows an insertion meter 200 having electrodes 210. Insertionmeter 200 and electrodes 210 are the same as insertion meter 100 andelectrodes 110, respectively, except that insertion meter 200 includestextured surface 230 on the front 220 of insertion meter 200. While thespecific configuration of textured surface 230 may vary based on theparticular operating conditions of the insertion meter (e.g., metercircumference, pipe diameter, pipe flow rate, fluid type, fluidvelocity, fluid density, etc.), the textured surface 230 should betextured sufficiently to trip or manipulate, the boundary layer suchthat the separation point (see, e.g., 105, FIG. 2) occurs consistentlyforward (towards front 220 of insertion meter 200, i.e., towards thesource of the flow) of the electrodes 210 for normal operatingconditions, and preferably all operating conditions, for the respectiveinsertion meter. In the illustrated embodiment, textured surface 230should be rougher than the remainder of sensor head tube 240 ofinsertion meter 200. For example, in one example, textured surface 230is rougher than the material forming the sensor head tube (e.g., smoothplastic and metal).

As shown in FIG. 7, textured surface 230 may be, for example, asandpaper or other similar abrasive on a substrate adhered to the sensorhead tube 240. Example abrasives on substrates include, for example,sand, glass, aluminum oxide, silicon carbide, emery cloth, pumice,crocus cloth, or the like. While this application discusses the use ofpaper as a substrate, other flexible substrates, for example, cloth,adhesive, or polymer, may also be used as well as inflexible substratesthat are formed or machined to the curvature of the outsidecircumference of the sensor head tube 240. In addition, the abrasivesmay further be impregnated or deposited into or onto the surface withouta substrate as an abrasive layer. The textured surface 230 may, in oneexample, extend the length of the sensor head tube 240 or be appliedlocally in the regions near electrodes 210. The amount of texture willdepend on the type of material used, the size and shape of the insertionmeter and flow pipe, and the characteristics of the fluid, but shouldnevertheless be sufficiently textured to manipulate the boundary layeras discussed above.

For example, a sandpaper textured surface 230 may include a 40-80 gritadhesive tape having a substrate thickness of about 0.030 inches andhaving a width of about 0.360 inches to about 0.400 inches, inclusive,the width being the dimension which would wrap around the circumferenceof the sensor head tube 240. The sandpaper textured surface may, in oneexample, be applied centered on the point of stagnation and along thefull length of the meter, or effectively the full length of the sensingportion of the meter sensor head tube 240.

FIG. 8 shows example meter outputs (SAND1-RUN1-90 deg throughSAND1-RUN3-90 deg) of an example insertion meter 200 (FIG. 7) as a graphof Meter Factor expressed as (Meter pulse/Ref Meter Pulse) againstnominal flow rate expressed in feet per second (ft/s). The differentline traces show repeated test runs of the same insertion meter 200 inthe same conditions. It is shown that both repeatability and linearityare improved over that of insertion meter 100 (FIG. 1). The improvedlinearity simplifies calibration and improves performance in differentpipes and fluids.

In an alternative example, instead of adding a textured substrate to thesurface of insertion meter sensor head tube, the texture is formeddirectly on the external surface of the sensor head tube. FIG. 9 showsan example embodiment of an insertion meter 300 having electrodes 310.Insertion meter 300 and electrodes 310 are the same as insertion meter200 and electrodes 210, respectively, except that textured surface ofinsertion meter 300 includes two longitudinal notches 330 or grooveswithin the sensor head tube 340 on the front 320 of insertion meter 300.The notches 330 run along the longitudinal axis of the insertion meters300 between the electrodes 310. The notches 330 also serve to manipulatethe boundary layer as discussed above with respect to insertion meter200.

In yet another embodiment, the textured surface includes columns ofdimples, for example, those dimples found in typical golf balls. Forexample, the textured surface may include a plurality of columns ofdimples. In one example, the textured surface includes about 3 to about7 columns of dimples. In another example, the textured surface includesmore than 7 columns of dimples. The specific textured surface featuresdiscussed above may also be combined. For example, the textured surfacemay include longitudinal grooves as well as columns of dimples. FIG. 10shows an insertion meter 400 of similar configuration as insertionmeters 300, 200, and 100, including for example having a plurality ofelectrodes including two top electrodes 410, two center or referenceelectrodes 411, and two bottom electrodes 412. As shown, however, thetextured surface of insertion meter 400 includes dimples 430 formed onor within the sensor head tube 440. The dimples 430 of insertion meter400 include 3 columns of dimples, with the center column 432 beingoffset longitudinally from the outer two columns 434 of dimples 430,which results in a pattern of one by two count rows. i.e. alternatingbetween 1 dimple and 2 dimple rows. In one example adjacent dimples 430form an equilateral triangle such that gap between any two dimples 430remain consistent. The dimples 430 extend the longitudinal length of thesensor head tube beyond the top electrodes 410 and bottom electrodes 412in both directions.

The dimples 430 may be formed as an additional surface that is added tothe sensor head tube 440 or may be formed within the sensor head tube440 by, for example, milling or during the formation of the sensor headtube 440 itself. While the size and configuration of each of the dimplescan be manipulated to depending on the particular sensor installation,as shown in FIG. 10 as one example, each of the dimples 140 have about a0.125 inch radius cut with a ¼″ ball end mill that is 0.020″ deep intosensor head tube 440. And adjacent dimple has about a 0.20 inch gapbetween them. In addition, the arc length between each hole in aspecific row (i.e., a dimple in one outer row 434 to a dimple in theother outer row 434 on the same radial plane) is about 35 to about 36degrees, inclusive, or specifically as shown about 35.35 degrees. Whilethe dimples 430 are only shown in FIG. 10 partially surrounding thesensor head tube 440, in an alternative example, the dimples 430 maymore fully surround, or even completely surround, the sensor head tube440.

FIGS. 11 and 12 are flow velocity stream models comparing insertionsensor 100 (FIG. 1) with insertion sensor 400 (FIG. 10) in the same flowconditions. In each of FIG. 11 and FIG. 12, the scales have beennormalized to 130 in/sec. As shown, separation point 110 is closer tothe electrode 105 than separation point 405 with respect to electrode410.

FIG. 13 shows an increase in linearity in the insertion meters with 7rows of dimples (shown as unfilled purple dots) as compared to thesmooth prior meters (shown in filled blue dots). The graph shows theability to extend the linearity within +/−1.5% of reading down to 1ft/sec of nominal flow rate with an example insertion meter with sevencolumns of dimples 430.

In another example embodiment, the cross-sectional shape of theinsertion meter is altered to affect the boundary layer/electrodeinteraction. For example; the insertion meter cross section can beformed in the shape of an oval or a tear drop to improve linearity andrepeatability. In such an embodiment the textured surface is itself asurface contour.

A method of measuring flow within a pipe or conduit is also disclosedherein. The methods include providing a magnetic insertion meter thatincludes a sensor head cylinder having a textured front surface and atleast two electrodes. Such insertion meters can be for example, thosediscussed above with reference to FIGS. 7-9 and their alternativeembodiments. In one example embodiment, the method includes measuringthe output of said electrodes.

It should be understood that the above description is only illustrativeof the invention. Various alternatives and modifications can be devisedby those skilled in the art without departing from the invention.Accordingly, the present invention is intended to embrace all suchalternatives, modifications and variances which fall with the scope ofthe appended claims.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A magnetic insertion meter comprising: a sensorhead cylinder having a textured front surface; and at least twoelectrodes.
 2. The insertion meter of claim 1, further comprising afield coil configured to emit an alternating magnetic field whenenergized with an alternating current
 3. The insertion meter of claim 1,wherein the textured front surface is an upstream surface.
 4. Theinsertion meter of claim 1, wherein the textured front surface is atleast one of an abrasive on a substrate, an impregnated abrasive, adeposited abrasive, and/or an abrasive layer.
 5. The insertion meter ofclaim 4, wherein the textured front surface is sandpaper.
 6. Theinsertion meter of claim 1, wherein the textured front surface has ahigher roughness than a material forming the sensor head tube.
 7. Theinsertion meter of claim 1, wherein the textured front surface includesat least one groove.
 8. The insertion meter of claim 7, wherein thetextured front surface includes two grooves extending along thelongitudinal axis of the sensor head cylinder.
 9. The insertion meter ofclaim 1, wherein the textured front surface includes dimples.
 10. Theinsertion meter of claim 9, wherein the plurality of dimples are equallyspaced apart from each other.
 11. The insertion meter of claim 10,wherein the plurality of dimples form a pattern in which three of theplurality of meters form an equilateral triangle.
 12. The insertionmeter of claim 9, wherein the textured front surface includes aplurality of columns of dimples
 13. The insertion meter of claim 12,wherein the textured front surface includes from about 3 to about 7columns of dimples.
 14. The insertion meter of claim 7, wherein thetextured front surface includes dimples.
 15. The insertion meter ofclaim 1, wherein the textured front surface is adapted to alter theboundary layer of a fluid flowing over the sensor head tube as comparedto the same sensor head tube without the textured front surface.
 16. Theinsertion meter of claim 1, wherein the textured front surface isadapted to move the separation point of a fluid flowing over the sensorhead tube towards the front surface as compared to the same sensor headtube without the textured front surface.
 17. The insertion meter ofclaim 1, wherein the textured surface is a surface contour.
 18. A methodof measuring flow, the method comprising, providing a magnetic insertionmeter that includes a sensor head cylinder having a textured frontsurface and at least two electrodes; and measuring the output of saidelectrodes.
 19. The method of claim 18, wherein the textured frontsurface is at least one of an abrasive on a substrate, an impregnatedabrasive, a deposited abrasive, and/or an abrasive layer.
 20. The methodof claim 18, wherein the textured front surface includes at least one ofdimples and/or grooves.